The present invention relates generally to urinary catheters and, more particularly, to an indwelling catheter, which permits the continuous collection of urine while reducing irritation of the urethra and diminishing the likelihoood of bacterial migration into the bladder.
In general, urinary catheters are intended to permit continuing collection of urine without leakage into a patient's clothing and bedding. To accomplish these functions, such catheters typically include means for retaining the catheter within the bladder, means for defeating the sphincter valve mechanism that normally closes the urethra, and a sterile system for transferring the collective urine to a suitable container.
The standard Foley catheter is a typical example of this type of retained urinary catheter. In simplest form, such catheters consist of a thick-walled elastic tube with an inflatable balloon at the end, which is inserted into the bladder. Although flexible enough to follow the curvature of the urethra to permit insertion, the tube is radially rigid in order to continually distend the urethra and neck of the bladder to allow continuous drainage of urine into a connected sterile tubing and container. Although effective for the intended purpose, such rigid tube catheters have several drawbacks. Normally, the urethra is a closed canal, opening only during the passage of urine, or semen in the male. This mechanism provides a barrier against the introduction of infection from outside the body into the urinary tract. The rigid-tube catheter continuously defeats this mechanism, thus increasing the incidence of infection. With normal body motion, the rigid tube also moves, chafing the urethral epithelium while also transmitting bacteria up into the bladder by a pumping/sliding action. Patient discomfort results, especially when there is a prolonged presence of the catheter.
The present invention is primarily directed to alleviation of the problems of infection and discomfort occasioned by the use of rigid-tube urinary catheters.